From: Pavel Begunkov <[email protected]>
To: [email protected]
Cc: Jens Axboe <[email protected]>,
[email protected], Oleg Nesterov <[email protected]>,
Andrew Morton <[email protected]>,
Christian Brauner <[email protected]>,
Tycho Andersen <[email protected]>,
Thomas Gleixner <[email protected]>,
[email protected], Julian Orth <[email protected]>
Subject: [PATCH 2/2] kernel: rerun task_work while freezing in get_signal()
Date: Sun, 7 Jul 2024 17:32:11 +0100 [thread overview]
Message-ID: <1d935e9d87fd8672ef3e8a9a0db340d355ea08b4.1720368770.git.asml.silence@gmail.com> (raw)
In-Reply-To: <[email protected]>
io_uring can asynchronously add a task_work while the task is getting
freezed. TIF_NOTIFY_SIGNAL will prevent the task from sleeping in
do_freezer_trap(), and since the get_signal()'s relock loop doesn't
retry task_work, the task will spin there not being able to sleep
until the freezing is cancelled / the task is killed / etc.
Cc: [email protected]
Link: https://github.com/systemd/systemd/issues/33626
Fixes: 3146cba99aa28 ("io-wq: make worker creation resilient against signals")
Reported-by: Julian Orth <[email protected]>
Signed-off-by: Pavel Begunkov <[email protected]>
---
kernel/signal.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/kernel/signal.c b/kernel/signal.c
index 1f9dd41c04be..790d60fcfff0 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2694,6 +2694,10 @@ bool get_signal(struct ksignal *ksig)
try_to_freeze();
relock:
+ clear_notify_signal();
+ if (unlikely(task_work_pending(current)))
+ task_work_run();
+
spin_lock_irq(&sighand->siglock);
/*
--
2.44.0
next prev parent reply other threads:[~2024-07-07 16:32 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-07-07 16:32 [PATCH 0/2] fix task_work interation with freezing Pavel Begunkov
2024-07-07 16:32 ` [PATCH 1/2] io_uring/io-wq: limit retrying worker initialisation Pavel Begunkov
2024-07-07 16:32 ` Pavel Begunkov [this message]
2024-07-08 10:42 ` [PATCH 2/2] kernel: rerun task_work while freezing in get_signal() Oleg Nesterov
2024-07-08 15:40 ` Pavel Begunkov
2024-07-08 18:48 ` Peter Zijlstra
2024-07-09 10:36 ` Oleg Nesterov
2024-07-09 14:05 ` Pavel Begunkov
2024-07-09 16:39 ` Tejun Heo
2024-07-09 19:07 ` Oleg Nesterov
2024-07-09 19:26 ` Pavel Begunkov
2024-07-09 19:38 ` Oleg Nesterov
2024-07-09 19:55 ` Pavel Begunkov
2024-07-10 0:54 ` Tejun Heo
2024-07-10 17:53 ` Pavel Begunkov
2024-07-10 19:10 ` Oleg Nesterov
2024-07-10 19:20 ` Tejun Heo
2024-07-10 21:34 ` Oleg Nesterov
2024-07-10 22:01 ` Tejun Heo
2024-07-10 22:17 ` Oleg Nesterov
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